Reference is made to commonly assigned U.S. Pat. No. 6,268,094 issued Jul. 31, 2001, entitled A PHOTOSENSITIVE MEDIA CARTRIDGE HAVING AN AMBIENT CONDITION SENSOR, filed concurrently herewith in the names of Loretta E. Allen, Yongcai Wang, Stephen M. Reinke and Yeh-Hung Lai; and U.S. Ser. No. 09/597,928 filed Jun. 19, 2000, entitled AN IMAGING ASSEMBLY AND MEDIA CARTRIDGE HAVING COOPERATING LINKAGE ARRANGEMENTS, filed concurrently herewith in the names of Loretta E. Allen, Yongcai Wang, Stephen M. Reinke and Yeh-Hung Lai.
The present invention relates to an imaging device for processing photosensitive media that includes a plurality of microcapsules that encapsulate imaging material such as coloring material. The present invention further relates a control arrangement for the imaging device which is responsive to ambient conditions and controls a pressure applied to the microcapsules in accordance with measured ambient conditions.
Image forming devices which process a photosensitive media that includes microcapsules which encapsulate coloring material are known. In these imaging devices the microcapsules are exposed to a radiation based on image information. The microcapsules, whose mechanical strength can change when exposed to light, are ruptured by means of a crushing pressure, whereupon the coloring material and other substances encapsulated in the microcapsules flow out and development occurs. For example, some systems use a pair of upper and lower nip rollers to apply pressure. In these systems, the photosensitive media is passed between the pair of upper and lower nip rollers which apply pressure to the microcapsules to rupture the microcapsules and begin development. Imaging devices that employ microencapsulted photosensitive compositions are disclosed in U.S. Pat. Nos. 4,399,209, 4,416,966, 4,440,846, 4,766,050, 5,783,353, and 5,916,727.
A problem in processing photosensitive media having microencapsulated color forming material is that printing and/or imaging can be adversely affected by ambient conditions. That is, ambient conditions around a printer housing, around the photosensitive media, or in the cartridge which carries the photosensitive media can adversely affect subsequent printing or development of the image. More specifically, ambient conditions such as humidity around the printer housing, at the photosensitive media or in the cartridge which houses the photosensitive media can have adverse affects on the chemicals of the coloring material, the encapsulating material, and/or the photosensitive media. Further, the degree of hardening or curing of the microcapsules and the consequent increase in viscosity of the microcapsule varies with a change in humidity. As a result, photographic characteristics such as speed, minimum and maximum density, fogging density and full color imaging can be adversely affected.
The present invention provides for an image forming device and method for processing photosensitive media that overcomes the above-mentioned drawbacks. More specifically, the present invention relates to an imaging device in which light sensitive media that contains light sensitive, rupturable microcapsules can be first exposed and then developed by applying pressure to the light sensitive media. In the image forming device of the present invention, print image quality can be improved by sensing ambient conditions such as humidity in the printer, directly from the media, or in the cartridge which carries the media, and adjusting at least one adjustable parameter based on the sensed ambient condition. As an example, in response to a sensed humidity condition, a controller or development member of the present invention can adjust the amount of pressure applied to the microcapsules.
As indicated above, in the imaging device of the present invention, the photosensitive medium contains light sensitive, rupturable microcapsules that are exposed and then developed by the application of pressure using a stylus or pinch rollers to rupture unexposed microcapsules. Thereafter, the developed print is fixed with heat supplied by a heater in the imaging device. In the present invention, the level of relative humidity can be sensed inside and/or outside of the printer, in the media cartridge or directly on the photosensitive media, and then at least one of the parameters of light exposure, developing pressure, printing speed or fixing temperature can be adjusted automatically on the basis of the relative humidity level to provide an improved image. As an example, by adjusting the printing speed for a printer, the so called xe2x80x9cdark timexe2x80x9d which is the time between exposure and development will be changed. The dark time affects the hardness of microcapsules and therefore their crushability. Also, within the context of the present invention, the concept of sensing the level of relative humidity on the photosensitive media refers to sensing the moisture content on the photosensitive media or material.
The imaging device of the present invention also includes an improved pressure assembly for applying a uniform pressure to the photosensitive media.
Accordingly, the present invention relates to an image forming device that comprises an imaging member for forming a latent image on a photosensitive medium, with the photosensitive medium comprising a plurality of microcapsules that encapsulate imaging material; a pressure assembly for applying pressure to the photosensitive medium to crush the microcapsules and develop the latent image; and a controller responsive to ambient conditions to provide a pressure increasing or a pressure decreasing signal to the pressure assembly and control an amount of pressure applied by the pressure assembly.
The present invention further relates to an image forming method that comprises the steps of conveying a photosensitive medium to an imaging member of an image forming device to form a latent image, with the photosensitive medium comprising a plurality of microcapsules that encapsulate imaging material; sensing ambient conditions and providing an ambient condition signal indicative thereof; and controlling an amount of pressure applied to the photosensitive medium based on the ambient condition signal to crush the microcapsules and develop the latent image.
The present invention further relates to an image forming method for developing photosensitive material having a plurality of microcapsules that encapsulate imaging material, with the method comprising the steps of sensing ambient conditions and providing an ambient condition signal indicative thereof; and controlling an amount of pressure applied to the photosensitive material based on the ambient condition signal to crush the microcapsules and develop a latent image on the photosensitive material.
The present invention further relates to an image forming method for developing photosensitive material in an image forming device which comprises the steps of sensing ambient conditions and providing an ambient condition signal indicative thereof; and controlling a development of the photosensitive material based on the ambient conditions.
The present invention further relates to an image forming device which comprises an ambient condition sensor for sensing ambient conditions; and a controller for controlling a development of photosensitive material in the image forming device based on the ambient conditions.
The present invention further relates to an image forming device which comprises a crushing roller for applying pressure on a first side of a photosensitive media, with the crushing roller being slidable along a widthwise direction of the photosensitive media; a beam for applying a pressure on a second side of the photosensitive media which is opposite the first side, so as to develop images on the photosensitive media as the media is conveyed between the crushing roller and the beam; and a flexible pressure strip provided between the crushing roller and the photosensitive media.
The present invention further relates to an image forming device which comprises an imaging member for forming a latent image on a photosensitive medium; a pressure assembly for applying pressure to the photosensitive medium to develop the latent image; and a controller responsive to ambient conditions to provide a pressure increasing or a pressure decreasing signal to the pressure assembly and control an amount of pressure applied by the pressure assembly.
The present invention further relates to an image forming device which comprises a pressure assembly for applying pressure to a photosensitive medium to develop an image on the photosensitive image; wherein the pressure assembly comprises a roller for applying pressure on a first side of the photosensitive medium with the roller being slidable along a widthwise direction of the photosensitive medium; and a beam for applying a pressure on a second side of the photosensitive medium which is opposite the first side, such that during development the photosensitive medium is conveyed between the roller and the beam. The beam is pivotally mounted about a pivot point and urged in a first direction about the pivot point by a spring force to a pressure applying position, such that the beam applies pressure against the second side of the photosensitive medium at the pressure applying position. The beam comprises a seat portion for holding an electromagnet therein, with the electromagnet applying an initial attraction force against the arm and the beam for maintaining the beam at the pressure applying position.
The present invention further relates to an image forming device which comprises a pressure assembly for applying pressure to a photosensitive medium to develop an image on the photosensitive medium; wherein the pressure assembly comprises first and second rollers which form a nip for the passage of the photosensitive medium therethrough, with the first and second rollers being mounted on a clamping spring which permits a uniform application of pressure at the nip by the first and second rollers across an entire width of the photosensitive medium and maintains the first and second rollers in a pressure applying position.
The clamping spring has a first section which rotatably holds one of the first and second rollers so that the one roller has a fixed rotational axis, and a second section which rotatably holds the other of the first and second rollers so that the other roller has an adjustable axis and is movable toward and away from the one roller.
The present invention further relates to an image forming device which comprises a pressure assembly for applying pressure to a photosensitive medium to develop an image on the photosensitive medium; wherein the pressure assembly comprises a roller for applying pressure on a first side of the photosensitive medium, with the roller being slidable along a widthwise direction of the photosensitive medium; a beam for applying a pressure on a second side of the photosensitive medium which is opposite the first side, such that during development the photosensitive medium is conveyed between the roller and the beam, with the beam being pivotally mounted about a pivot point and urged in a first direction about the pivot point by a spring force to a pressure applying position, such that the beam applies pressure against the second side of the photosensitive medium at the pressure applying position; and an extension spring which extends from the beam. The extension spring is operationally associated with a stepper motor for controlling a movement of the beam about the pivot point.